Experimental results for nitrogen condensation into silica pores. Dielectric measurements at microwave frequencies

1990 ◽  
Vol 93 (9) ◽  
pp. 6779-6786 ◽  
Author(s):  
Francis Biquard ◽  
Robert Guermeur ◽  
Christian Jacolin
2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ethar Y. Salih ◽  
Zulkifly Abbas ◽  
Samer Hasan Hussein Al Ali ◽  
Mohd Zobir Hussein

Recently, researchers have shown great interest in improving the thermal, mechanical, dielectric, and microwave properties of pure polymers through the use of polymer-based composites. The essential properties of polymer-based composites can be modified by varying the amount of Zn/Al-NO3layered double hydroxide (LDH) added to polyvinyl chloride (PVC). Therefore, by determining the optimal ratio of LDH in the PVC matrix, the dielectric properties of PVC-LDH composites can be improved. An LDH was prepared using the coprecipitation method, while PVC-LDH composites were prepared using tetrahydrofuran (THF) as the solvent. The composites were characterised using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), and room temperature dielectric measurements were investigated using an RF Impedance/Material Analyzer (Agilent 4291). The results confirmed that the prepared composites were pure. Additionally, the presence of LDH in the PVC matrix was verified. The dielectric measurements showed that an increase in the LDH concentration leads to an increase in the dielectric constant and the dielectric loss factor. When used as dielectric filler in the PVC matrix, the LDH improved the dielectric properties of the fabricated composites. The results indicate that these composites show great potential for use as microwave absorbers at low microwave frequencies.


Nature ◽  
1951 ◽  
Vol 167 (4250) ◽  
pp. 607-608 ◽  
Author(s):  
G. H. HAGGIS ◽  
T. J. BUCHANAN ◽  
J. B. HASTED

2003 ◽  
Vol 17 (04n06) ◽  
pp. 535-541 ◽  
Author(s):  
A. AGLIOLO GALLITTO ◽  
G. BONSIGNORE ◽  
M. LI VIGNI

We report a set of experimental results on microwave third-harmonic emission by MgB 2 superconductor. We have investigated third-harmonic signals as a function of temperature, input power level and intensity of the static magnetic field. We show that different mechanisms are responsible for third-harmonic emission at temperatures near T c and far below T c , similarly to what has been obtained in other high- T c superconductors.


Sign in / Sign up

Export Citation Format

Share Document